1. Victims were older, usually over 60.
2. Victims were overweight.
3. Victims led inactive lives.
4. Victims were alcoholics.
5. Women were more prone to spontaneously combust than men.
6. At the scene there was often an external flame, such as a candle or fireplace.
7. Combustion was extremely rapid.
8. The flames were difficult to extinguish.
9. The flames produced a strong empyreumatic odor.
10. The surrounding room was coated with a thick, yellow, greasy film.
11. The first usually consumed the trunk of the body, but left the head and extremities intact.
12. Accidents occurred during fair weather, and more often in winter than in summer.
Are you at risk for spontaneous combustion? Check out these tell-tale signs from a physician in 1799.  (via laphamsquarterly)